“While we are seeing more investors collecting, there are many more collectors who are increasing their investment in their collections as the explosion of interest in art, fuelled by globalisation, facilitated by the technology that increases access to information and images, meets the art that is coming to the market.”

The auction house said first-time buyers increase by 12%, and demand from China and Russia continues to grow.

Chinese buyers accounted for 13% of sales last year, a 2% increase on 2010, and the number of customers from Russia and former Soviet Union countries increased by 15%.

Murphy said international trade had been boosted by the company’s revamped Christies.com website.

Traffic to the site increased by 77% last year, and almost one in three bids were placed online.

However, customers are still reluctant to buy the most expensive paintings through the internet – just two of the 719 works that sold for more than m (£630,000) were bought via online bidding.